1. Technical Field
The present disclosure relates to trocar systems for inserting cannulas into patients, and more particularly to modular trocar systems and methods of assembly of trocar systems.
2. Background of Related Art
Minimally invasive surgical procedures where trocar systems are desirable or even necessary are continually increasing in number and variety. These procedures call upon surgeons to utilize an array of variously sized surgical equipment, e.g., graspers, dissectors, clip appliers, staplers, retractors, imaging systems, and the like. Accordingly, trocar assemblies having variously sized obturators and cannulas are required, e.g. 3-15 mm, to facilitate the range of minimally invasive procedures while minimizing the size of each trocar entry to the extent possible.
Presently, placement of each different diameter cannula requires the use of a specially sized obturator assembly. In other words, to introduce a 5 mm cannula, a 5 mm obturator is required; to introduce a 10 mm cannula, a 10 mm obturator is required; and so on. Manufacturers of trocar assemblies must therefore produce and inventory numerous different sized housings and operative components to allow the manufacture of each particular obturator and cannula variation to be marketed. For obvious commercial reasons, health care providers and medical equipment distributors of trocar assemblies must maintain appropriate inventories of each product variation to meet customer demand as it arises.
WO 95/07663 to Vidal et al. discloses one approach to addressing the variety of customer needs in the field of trocar assemblies. Vidal et al. disclose a plurality of obturator tips that are adapted to be removably received by an obturator shaft, e.g., through a detent/leaf spring arrangement or a lug/groove arrangement. While a variety of cutting blade geometries are proposed from which the surgeon may select, each of the disclosed obturator tips is the same diameter so that the completed obturator assembly may be utilized with a cannula of preselected diameter.
It is also known to provide operative surgical instruments with interchangeable working ends. For example, WO 94/13335 to Dorsey discloses a "quick disconnect" arrangement for a suction/irrigation system that allows interchange between a variety of probes of differing shapes and orientation. See also U.S. Pat. No. 5,322,503 to Desai which discloses an instrument that is adapted to receive a variety of electrostatic probes.
A further factor of significance in the design and use of trocar systems is the ease with which the trocar system passes through the body wall so as to position the cannula thereacross. Thus, efforts have been expended to minimize the penetration force of the trocar system while maintaining maximum surgeon control and safety. U.S. Pat. No. 4,601,710 to Moll discloses several trocar designs which include a spring biased safety shield adapted to cover the cutting blade upon entry into the body cavity. In one embodiment (see FIGS. 1-5B), the safety shield is slotted and the blade is configured to extend through the slots, thereby increasing the effective diameter of the blade incision. See also U.S. Pat. No. 5,066,288 to Deneiga et al.
Despite these earlier efforts in the fields of interchangeability, a need exists for a trocar system that is truly modular. That is, a trocar system wherein various components thereof may be readily interchangeable and certain components standardized to facilitate manufacture and use across a broader spectrum of product lines.
Moreover, improvements in trocar design which might minimize penetration force while maintaining surgeon control and safety during trocar penetration are always warranted and to be welcomed.